过渡段形式对无喉道量水槽水力特性的影响

Influence of Transition Section on Hydraulic Characteristics of Cut-throat Flume

为了对比不同过渡段形式对无喉道量水槽水力特性的影响,在传统矩形无喉道量水槽结构的基础上,设计了过渡段为圆形和椭圆形的无喉道量水槽,在宽0.6 m,深0.3 m的矩形渠道上进行了一系列试验。试验测量了无喉道量水槽在不同流量下的水位,对水位流量关系进行拟合,对不同流量下的佛汝德数和水头损失进行了分析。结果表明,过渡段形式对无喉道量水槽的测流精度、佛汝德数及水头损失均有一定影响。3种无喉道量水槽的槽前水流均满足测流要求,直线形过渡段无喉道量水槽的测流精度最高,但水头损失最大;圆形过渡段无喉道量水槽的测流精度虽较直线形过渡段的低,但水头损失最小。

To compare the effects of different transition sections on hydraulic characteristics of cut-throat flume, two cut-throat flumes with circular transition section and oval transition section based on traditional structure were designed. A series of experiments were carried on these cut-throat flumes, which emplaced in a rectangular channel with 0.6 m width and 0.3 m depth. The experiments measured water depths for different discharges. The relations between water depth and discharge were fitted out. The Froude Number and the head losses under differ- ent discharges were analyzed. The results showed that the flow measurement precision, the Froude Number and the head losses were influenced by transition sections of cut-throat flume. The upstream flow of these three cutthroats could meet the requirement. The cut-throat flume with rectilinear transition section had the highest flow measurement precision and the largest head losses. The cut-throat flume with circular transition section had lower flow measurement precision, compared with the rectilinear transition section, but had the lowest head losses.